How to transfer data to a new container without loss?

Question

linux

Hello! The crux of the matter is as follows. I have a container with Nextcloud, data and database on separate "hosts".
DB (postgres), storage is connected via nfs. The official Nextcloud container has been released. It is not possible to run it on existing data and databases.
I launch a new container and send it to the previously used directories (of the previous one) and pass it in the database variables when launching the image.
I don’t understand where the error is to look for the container works, it doesn’t fall off. I go inside the container, the directories inside it are mounted, but the APP does not respond?
I also check the BD variable inside the container is correct.
When starting the container, no config is created. I copy the config by hand and edit it to fit the needs.
What could be the problem ? In which direction to dig, how to debug an error?
docker logs container - doesn't show anything useful.

Answer 1

If the data is stored outside the container, then everything should start normally upon restart.
When restarting the old container, does it start correctly?
If so, then the matter is most likely in the different giblets of the new container. Therefore, you need to compare the contents of the Dockerfile, entrypoint.sh of the old and new containers.
If you're having trouble restarting an older version of a container, it's likely that the resource where the container's external data is stored is disabled or otherwise mounted.